The present invention relates to an apparatus adapted to turn round a series of predetermined articles successively. The present application is based on, and claims priority from, Japanese Application Serial Number 2002-333358, filed Nov. 18, 2002, the disclosure of which is hereby incorporated by reference herein in its entirety.
Japanese Patent Application Publication No. 1996-310705A discloses a work turning-round apparatus proposed, which successively turns round a plurality of works fed at regular intervals by an angle of 90° relative to a direction in which the works are conveyed. These works are held on the apparatus in the course of being turned round.
The work turning-round apparatus disclosed in the above-cited Publication comprises a guide rail presenting a substantially oval profile, an endless conveyor circularly running along the guide rail, a plurality of carriages mounted on the endless conveyor and moving on the guide rail, table bases rotatably mounted on the carriages and work tables mounted on the table bases integrally therewith. The endless conveyor has a loading station and an unloading station for the sheet-like works and a pair of connecting conveyor sections extending between the loading station and the unloading station. In the case of this well-known work turning-round apparatus, rectilinear sections of the guide rail define the loading station and the unloading station, respectively, and curved sections of the guide rail define the connecting conveyor sections, respectively.
With this work turning-round apparatus, the works are held, at the loading station, on the respective work tables of the carriages and travel toward the unloading station through one of the connecting conveyor sections as the endless conveyor runs. Each of the table bases rotates by an angle of 90° relative to the associated carriage around its axis extending in a direction crossing the direction in which the works are conveyed and thereby turns round the work held on the work table by the corresponding angle. At the unloading station, this work is conveyed away from the turning-round apparatus. After the work has been conveyed away from the turning-round apparatus, the table base rotates again by an angle of 90° relative to the associated carriage, at the other of the connecting conveyor sections, around its axis crossing the direction in which the works are conveyed. In this way, each of the works rotates by an angle of 180° while the associated table base makes a circuit of the guide rail.
With the work turning-round apparatus disclosed in the above-cited Publication, the table bases can be rotated along the connecting conveyor sections but can be rotated neither at the loading station nor at the unloading station. This is for the reason that the guide rail rectilinearly extends at the loading and unloading stations and a plurality of the table bases closely lined up along these stations. If it is intended to rotate a pair of the adjacent table bases along the rectilinear sections of the guide rail defined by the loading and unloading stations, these table bases will bump against each other and prevented from smoothly rotating. Along the curved connecting conveyor sections, on the other hand, there is a difference in level between each pair of the adjacent table bases and therefore each of these adjacent table bases can be rotated without any interference with each other.
This work turning-round apparatus is constructed so that the table bases rotate around their own axes along the curved sections of the guide rail (i.e., connecting conveyor sections) and loading as well as unloading of the works is carried out along the rectilinear sections of the guide rail (i.e., the loading station and the unloading station). Thus a restriction is imposed on the positions on the apparatus at which the works are loaded and are unloaded.
In this work turning-round apparatus, the carriages travel on the guide rail by means of guide rollers mounted on these carriages and a plurality of the table bases rotate on their own axes while these table bases travel on the guide rail. Such construction not complicates the structure of the apparatus but also is unsuitable for the purpose of turning round the works at a high velocity.